Risk stratification of submandibular salivary gland involvement in oral squamous cell carcinoma based on histopathological parameters: A 15-year retrospective study.

Objective: Squamous cell carcinoma (SCC) represents about 90% of all oral malignancies. The study aimed to assess the involvement of the submandibular salivary gland (SMG) in oral SCC (OSCC) patients and the need for SMG excision.

Materials and methods: Demographics, clinical information and staging of the 210 patients undergoing surgery for OSCC were obtained from the department records. The histopathological slides were retrospectively reviewed. The nodal status was also verified with the histopathology reports. Frequency distribution, Chi-square association, ordinal logistic regression analysis and Kaplan-Meier analysis were performed.

Results: SMG was excised in 171 patients. Five patients had SMG involvement. Buccal mucosa (BM) and gingivobuccal sulcus had a greater risk of level IB metastases (P < 0.01). Pattern 3 and pattern 4 of invasion had a higher risk of level IB metastases (P = 0.04). Depth of invasion (DOI) >4 mm was associated with level IB lymph node (LN) involvement (P = 0.0001). DOI >4 mm to 8 mm had 3.7 times the risk and a DOI >8 mm to 12 mm had 5 times the risk of level IB metastases. Pattern of invasion (POI), tumour budding and DOI >4 mm were significant prognosticators for patient survival.

Conclusion: Histologically, patients may be categorised as 'high risk': those with an increased risk of level IB LN involvement and 'low risk': those at low risk for level IB involvement with the help of POI, tumour budding and DOI as risk factors. In low-risk patients, SMG may be spared and the level IB LNs are dissected. High-risk patients may be chosen as candidates for SMG transfer or excision based on the extent of LN involvement.